Fundamental changes are underway in how humans useenergy. We started deploying coal at large scale around 1850,petroleum around 1900, and natural gas around 1950.Consumption of these fossil fuels increased dramatically inthe last 50 years, helping to enable an unprecedented pace ofhuman and economic development. However, continued growthin deployment of these fuels, which formed from the decay oforganic matter over millions of years, will not be possible, giventhey are replenished mor